xfs: xfs_bmapi_read doesn't take a fork id as the last argument

The last argument to xfs_bmapi_raad contains XFS_BMAPI_* flags, not the
fork.  Given that XFS_DATA_FORK evaluates to 0 no real harm is done,
but let's fix this anyway.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>